Kidney stones, also called renal calculi, are solid crystal aggregations of dissolved minerals in urine. Depending on their location in the urinary tract these calculi are called by various names, e.g., kidney stones, ureteric stones, bladder stones, or urethral stones. Most kidney stones are caused by the precipitation of calcium in the form of calcium oxalate. A minority of stones may also be caused by or include precipitated calcium hydroxyl phosphate (apatite), magnesium ammonium phosphate (struvite), uric acid, or cysteine. In addition to excruciating pain, symptoms of kidney stones may also include blood in the urine due to minor damage to inside lining of kidney, ureter, and urethra; reduced urine volume caused by obstruction of the bladder or urethra by the stones; kidney infection as a result of stone blockage; abdominal distention; nausea or vomiting; and fever and chills.
Kidney stone disease is an ailment afflicting human kind for many centuries. It can affect up to a quarter of the population in certain geographic areas and hence poses a significant health problem. Approximately 85% of the stones in human are calcium stones comprising oxalate and phosphate, either alone or combined. The pathogenesis of calcium oxalate stone formation is a multi-step process and in essence includes—nucleation, crystal growth, crystal aggregation, and crystal retention. Various substances in the body have an effect on one or more of the above stone forming processes, thereby influencing a person's ability to promote or prevent stone formation. Low urine volume, low urine pH, calcium, sodium, oxalate, and urate are known to promote stone formation. Many inorganic (e.g., magnesium) and organic (e.g., urinary prothrombin fragment 1, glycosaminoglycans, osteopontin, citrate) substances are known to inhibit stone formation.
The initiation of growth of a calcium oxalate stone is thought to occur at sites of inflammation or damage within the kidney. The stones form by an initial deposition of calcium crystals at the sites of inflammation or damage and are known in the literature as Randall's plaques. These Randall's plaques then serve as nuclei for formation of calcium oxalate on top of the calcium hydroxyapatite mini-stones. Once of a certain size, stones often fragment or a break off from the Randall plaque region and can either pass out of the body or get stuck along the urinary tract, resulting in clinical symptoms such as reduced urine flow, pain or bleeding.
Prevalence of kidney stones in the United States has been estimated at 8.8% (roughly 1 in 11 people). Among men, the prevalence of stones was 10.6%, compared with 7.1% among women. Kidney stones were more common among obese than normal-weight individuals. (Eur Urol. 2012 July; 62(1):160-5.)
Reoccurrence of stones in patients has been estimated to be as high as 50 percent within 5 years of the initial event. Rates of emergency department visits for kidney stone disease have increased 20 percent between 2005 and 2009.
In 2014, one study suggested that kidney stone interventions cost an estimated $10 billion annually in the United States and patients who have an unplanned hospital visit for kidney stones incur average costs of nearly $30,000, depending on the type of procedure and the subsequent care. (Duke University Medical Center. “Complications from kidney stone treatments are common, costly” ScienceDaily. 28 Apr. 2014)
Medical treatment options depend on severity of pain, size of stone, and location of stone. Smaller stones will often pass on their own. For larger stones, some form of intervention is usually required and include: ureteroscopy and laser stone lithotripsy (the stone is located with a small camera inserted into the urethra and removed with a small basket or broken up with a laser); extracorporeal shockwave lithotripsy (ESWL; breaks up stone from the outside of the body with shockwaves that travel through a gel-like medium); Percutaneous Nephrolithotomy (PCNL; inpatient procedure for very large stones, which typically requires an overnight hospital stay). If patient has more than one kidney stone or stone occurrence, physician often recommends getting a special urine study done. A 24-hour urine study will show the composition of urine in relation to kidney stone formation. Diet can be altered or improved based on these results to help in preventing reoccurrence of a stone. Rarely patients are placed on a prescription medication as the options are very limited and can have serious side effects or risks for the patient. Sometimes pain medications are utilized as the stone is passing through the person's system. One goal in diet alteration is to try to prevent crystal formation. Common recommendations include: drink more water, often at least 6-8 glasses per day; decrease caffeine intake; eliminate colas due to phosphoric acid content; drink lemon water; decrease sodium, sugar, and red meat and oxalate-rich foods (e.g., Spinach, strawberries, nuts, tea); and increase fiber intake.
Various active agents are known to have an effect on kidney stones, including citric acid, magnesium citrate, phytin, pyridoxine, and musa, however, these active agents have not been combined in one composition, nor have they been combined in amounts that maximize the percent inhibition of crystal formation.
Thus, there remains a need for a simple and effective method and composition for preventing and treating kidney stones that optimizes the inhibition of crystal formation.